CDMA : Full BW, All
Not full RF power.
One Frequency in all the
Freq. Reuse Factor = 1
Entire BW used by each user
at the Same time
Channelization Codes (SF) Scrambling Codes
Data Rate Chip Rate Chip Rate
Channelization codes : Increases Signal BW ; Uses
Scrambling codes : Does not Increase Signal BW ; Uses
Pseudo noise codes
How to Differentiate Cells and Users ?
Based on OVSF (Orthogonal Variable Spreading Factor)
Differentiate users within a sector
What If Two Sectors use the same OVSF code ?
OVSF Code Tree
What is “Spreading Factor” ?
Q). For a 12.2kbps Voice call what is the required SF ?
(Chip Rate : 3.84 Mcps)
Also Known as Processing Gain
No Dedicated Channels any more
High speed Shared Channel
Retransmission and Scheduling
TTI : 10ms 2ms
Adaptive Modulation (QPSK and 16 QAM) and
Dedicated Channel Vs Shared Channel
Shared Channel is much more efficient than a dedicated
channel to carry bursty Packet traffic
High Speed Downlink Shared Channel (HS-DSCH)
HS – PDSCH : For DL data tx.,Up to 15
codes, SF 16
HS – SCCH : For DL control info. Tx., Up
to 4 codes, SF 128
HS – DPCCH : For UL tx. (CQI,
ACK/NACK), SF 256
Transport channel used mainly for data
Contains three main Physical layer channels
Resource Sharing in HSDPA…..
2ms TTI 2ms TTI 2ms TTI
An Example of throughput reduction with number of
High Speed Packet Access - HSPA
HSUPA : Designed to increase the uplink throughput over the air
Theoretical peak user bit rate : 5.76 Mbps
Enhanced Dedicated Channel (E-DCH) in UL
HSDPA + HSUPA
Q). Calculate the max. possible throughput that
can be achieved with HSPA+
16 QAM, QPSK 64 QAM
HSPA+ Vs DC-HSPA+….
Single Stream Dual Streams
f1, f2 : 5MHz carriers
HSPA+ vs DC-HSPA+….
HSPA+ DC -HSPA+
Users are served using only one
two carriers have been aggregated
together to provide high speeds to
Anchor Carrier : Both UL and DL
Supplementary Carrier : Only for DL
About Two carriers……
Other Advantages :
HSDPA Carrier load balancing : High Radio Resource
DC-HSPA+ is backward compatible with earlier
Releases of 3G (R’99, Rel.5, Rel.6 and Rel.7)
High Spectrum efficiency
DC-HSPA+ Test ResultsPeak Throughput
@ Rotunda Tower.
From Local File Server :Torrentz :
Test Results from BagathaleRd
With DC -HSPA+
Test Results at Malabe
With HSPA+ With DC -HSPA+
Can all of us archive these higher
Speeds, beyond 21Mbps ??
Need to have DC-HSPA+ capable device with correct APN
• Dongle, phone, Tab WiFi router
Need to use a application which need this much of higher
• Eg: Will not get high speed by watching HD Youtube
The server side also need to have the capability to support
• Eg: Torrent download can have limitation from sever side
No improvement on UL with this technology
Why 32 Mbps max?
42 Mbps is the Theoretical max. achievable in
No of Codes used : 14